Thanks for the note. Softcover is absolutely amazing for my purposes, but at this point we think the educational market is more promising than the market for self-publishing tools, so that's what we're focusing on now. This was always part of our plan; I personally needed Softcover for the reasons you mention, but it was an open question whether it would take off as a standalone platform or whether we would end up focusing on making our own products.

A happy but unintended side-effect of making a platform is that it dramatically lowers the barrier to collaborating with other authors, and I'm currently working with several other people on more advanced and varied Learn Enough tutorials. This sort of collaborative publishing (with full control over the publication pipeline) would be effectively impossible without Softcover.